3TSG image
Entry Detail
PDB ID:
3TSG
Keywords:
Title:
Crystal structure of GES-14
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2011-09-13
Release Date:
2012-09-26
Method Details:
Experimental Method:
Resolution:
1.90 Å
R-Value Free:
0.20
R-Value Work:
0.16
R-Value Observed:
0.16
Space Group:
P 2 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Extended-spectrum beta-lactamase GES-14
Chain IDs:A, B
Chain Length:287
Number of Molecules:2
Biological Source:Acinetobacter baumannii
Primary Citation
Kinetic and crystallographic studies of extended-spectrum GES-11, GES-12, and GES-14 beta-lactamases.
Antimicrob.Agents Chemother. 56 5618 5625 (2012)
PMID: 22908160 DOI: 10.1128/AAC.01272-12

Abstact

GES-1 is a class A extended-spectrum β-lactamase conferring resistance to penicillins, narrow- and expanded-spectrum cephalosporins, and ceftazidime. However, GES-1 poorly hydrolyzes aztreonam and cephamycins and exhibits very low k(cat) values for carbapenems. Twenty-two GES variants have been discovered thus far, differing from each other by 1 to 3 amino acid substitutions that affect substrate specificity. GES-11 possesses a Gly243Ala substitution which seems to confer to this variant an increased activity against aztreonam and ceftazidime. GES-12 differs from GES-11 by a single Thr237Ala substitution, while GES-14 differs from GES-11 by the Gly170Ser mutation, which is known to confer increased carbapenemase activity. GES-11 and GES-12 were kinetically characterized and compared to GES-1 and GES-14. Purified GES-11 and GES-12 showed strong activities against most tested β-lactams, with the exception of temocillin, cefoxitin, and carbapenems. Both variants showed a significantly increased rate of hydrolysis of cefotaxime, ceftazidime, and aztreonam. On the other hand, GES-11 and GES-12 (and GES-14) variants all containing Ala243 exhibited increased susceptibility to classical inhibitors. The crystallographic structures of the GES-11 and GES-14 β-lactamases were solved. The overall structures of GES-11 and GES-14 are similar to that of GES-1. The Gly243Ala substitution caused only subtle local rearrangements, notably in the typical carbapenemase disulfide bond. The active sites of GES-14 and GES-11 are very similar, with the Gly170Ser substitution leading only to the formation of additional hydrogen bonds of the Ser residue with hydrolytic water and the Glu166 residue.

Legend

Protein

Chemical

Disease

Primary Citation of related structures